A novel siphon-based divide-and-conquer(SbDaC)policy is presented in this paper for the synthesis of Petri net(PN)based liveness-enforcing supervisors(LES)for flexible manufacturing systems(FMS)prone to deadlocks or l...A novel siphon-based divide-and-conquer(SbDaC)policy is presented in this paper for the synthesis of Petri net(PN)based liveness-enforcing supervisors(LES)for flexible manufacturing systems(FMS)prone to deadlocks or livelocks.The proposed method takes an uncontrolled and bounded PN model(UPNM)of the FMS.Firstly,the reduced PNM(RPNM)is obtained from the UPNM by using PN reduction rules to reduce the computation burden.Then,the set of strict minimal siphons(SMSs)of the RPNM is computed.Next,the complementary set of SMSs is computed from the set of SMSs.By the union of these two sets,the superset of SMSs is computed.Finally,the set of subnets of the RPNM is obtained by applying the PN reduction rules to the superset of SMSs.All these subnets suffer from deadlocks.These subnets are then ordered from the smallest one to the largest one based on a criterion.To enforce liveness on these subnets,a set of control places(CPs)is computed starting from the smallest subnet to the largest one.Once all subnets are live,this process provides the LES,consisting of a set of CPs to be used for the UPNM.The live controlled PN model(CPNM)is constructed by merging the LES with the UPNM.The SbDaC policy is applicable to all classes of PNs related to FMS prone to deadlocks or livelocks.Several FMS examples are considered from the literature to highlight the applicability of the SbDaC policy.In particular,three examples are utilized to emphasize the importance,applicability and effectiveness of the SbDaC policy to realistic FMS with very large state spaces.展开更多
In recent years,there has been an increasing need for climate information across diverse sectors of society.This demand has arisen from the necessity to adapt to and mitigate the impacts of climate variability and cha...In recent years,there has been an increasing need for climate information across diverse sectors of society.This demand has arisen from the necessity to adapt to and mitigate the impacts of climate variability and change.Likewise,this period has seen a significant increase in our understanding of the physical processes and mechanisms that drive precipitation and its variability across different regions of Africa.By leveraging a large volume of climate model outputs,numerous studies have investigated the model representation of African precipitation as well as underlying physical processes.These studies have assessed whether the physical processes are well depicted and whether the models are fit for informing mitigation and adaptation strategies.This paper provides a review of the progress in precipitation simulation overAfrica in state-of-the-science climate models and discusses the major issues and challenges that remain.展开更多
Nitrate contamination of groundwater is a worldwide problem, particularly in agricultural countries. Exposure to high levels of nitrates in groundwater can have adverse effects on the health of residents who use groun...Nitrate contamination of groundwater is a worldwide problem, particularly in agricultural countries. Exposure to high levels of nitrates in groundwater can have adverse effects on the health of residents who use groundwater for drinking. This study aims to assess the health risk associated with the ingestion of nitrates in well water in the town of M’bahiakro. Health risk maps were created on the basis of hazard quotients (HQ) using the US Environmental Protection Agency (USEPA) health risk assessment model. The results indicate that residents of the Koko, Dougouba and Baoulekro neighbourhoods, whatever their age, are potentially exposed to the toxic effects of NO3−during their daily intake of nitrate-contaminated well water, with reference to hazard quotients (HQ) greater than 1. Nitrate concentrations in the groundwater should therefore be controlled in order to prevent their harmful effects on the health of the population and guarantee its use in rice-growing activities in M’Bahiakro.展开更多
The objective of this study is to propose an optimal plant design for blue hydrogen production aboard a liquefiednatural gas(LNG)carrier.This investigation focuses on integrating two distinct processes—steam methaner...The objective of this study is to propose an optimal plant design for blue hydrogen production aboard a liquefiednatural gas(LNG)carrier.This investigation focuses on integrating two distinct processes—steam methanereforming(SMR)and ship-based carbon capture(SBCC).The first refers to the common practice used to obtainhydrogen from methane(often derived from natural gas),where steam reacts with methane to produce hydrogenand carbon dioxide(CO_(2)).The second refers to capturing the CO_(2) generated during the SMR process on boardships.By capturing and storing the carbon emissions,the process significantly reduces its environmental impact,making the hydrogen production“blue,”as opposed to“grey”(which involves CO_(2) emissions without capture).For the SMR process,the analysis reveals that increasing the reformer temperature enhances both the processperformance and CO_(2) emissions.Conversely,a higher steam-to-carbon(s/c)ratio reduces hydrogen yield,therebydecreasing thermal efficiency.The study also shows that preheating the air and boil-off gas(BOG)before theyenter the combustion chamber boosts overall efficiency and curtails CO_(2) emissions.In the SBCC process,puremonoethanolamine(MEA)is employed to capture the CO_(2) generated by the exhaust gases from the SMR process.The results indicate that with a 90%CO_(2) capture rate,the associated heat consumption amounts to 4.6 MJ perkilogram of CO_(2) captured.This combined approach offers a viable pathway to produce blue hydrogen on LNGcarriers while significantly reducing the carbon footprint.展开更多
This study develops an analytical model to evaluate the cooling performance of a porous terracotta tubular direct evaporative heat and mass exchanger. By combining energy and mass balance equations with heat and mass ...This study develops an analytical model to evaluate the cooling performance of a porous terracotta tubular direct evaporative heat and mass exchanger. By combining energy and mass balance equations with heat and mass transfer coefficients and air psychrometric correlations, the model provides insights into the impact of design and operational parameters on the exchanger cooling performance. Validated against an established numerical model, it accurately simulates cooling behavior with a Root Mean Square Deviation of 0.43 - 1.18˚C under varying inlet air conditions. The results show that tube geometry, including equivalent diameter, flatness ratio, and length significantly influences cooling outcomes. Smaller diameters enhance wet-bulb effectiveness but reduce cooling capacity, while increased flatness and length improve both. For example, extending the flatness ratio of a 15 mm diameter, 0.6 m long tube from 1 (circular) to 4 raises the exchange surface area from 0.028 to 0.037 m2, increasing wet-bulb effectiveness from 60% to 71%. Recommended diameters range from 5 mm for tubes under 0.5 m to 1 cm for tubes 0.5 to 1 m in length. Optimal air velocities depend on tube length: 1 m/s for tubes under 0.8 m, 1.5 m/s for lengths of 0.8 to 1.2 m, and up to 2 m/s for longer tubes. This model offers a practical alternative to complex numerical and CFD methods, with potential applications in cooling tower optimization for thermal and nuclear power plants and geothermal heat exchangers.展开更多
Introduction: Renal ischemia-reperfusion (IR) is responsible for injuries such as destruction or dysfunction of tubular epithelial cells with inflammatory reaction and oxidative stress. Several therapeutic methods hav...Introduction: Renal ischemia-reperfusion (IR) is responsible for injuries such as destruction or dysfunction of tubular epithelial cells with inflammatory reaction and oxidative stress. Several therapeutic methods have been tested to alleviate ischemia-perfusion injury, ranging from using anti-inflammatory drugs, antioxidants, and plants from traditional pharmacopeia to administering RNA interference. However, there is currently no effective therapeutic option available for the treatment of renal IR injury, other than supportive therapies such as renal replacement therapy or hydration. Objective: This present study aimed to evaluate the effect of Guiera senegalensis on renal ischemia reperfusion, a recognized plant for its antioxidant and anti-inflammatory properties. Materials and Methods: Twenty-four (24) adult male Wistar rats were divided into four following groups: SLAM (subjected to a median laparotomy with simulated ischemia);GUIERRA (animals that received 250 mg/kg of guierra senegalensis orally, once a day, for 5 days, with simulated renal ischemia);IR (animals that underwent laparotomy followed by clamping of bilateral renal pedicles for 45 min and followed by reperfusion);GUIERRA + IR (animals given GUIERRA at the dosage of 250 mg/kg per day, for 5 days and then subjected to renal ischemia-reperfusion). Data analysis was performed by ANOVA, and a significance level of p Results: Compared with the I/R group, rats in the GUIERRA + IR group showed reduced histopathological damage scores (p Conclusion: The results of this preliminary work suggest that Guiera senegalensis decreases the degree of tissue damage in renal ischemia-reperfusion cases. This plant seems to be a promising therapeutic;further studies could help to precise the targets of its compounds on ischemia-reperfusion pathways.展开更多
This research aims to study the bio-adsorption process of two dyes,Cibacron Green H3G(CG-H3G)and Terasil Red(TR),in a single system and to bring them closer to the industrial textile discharge by a binary mixture of t...This research aims to study the bio-adsorption process of two dyes,Cibacron Green H3G(CG-H3G)and Terasil Red(TR),in a single system and to bring them closer to the industrial textile discharge by a binary mixture of two dyes(TR+CG-H3G).The Cockle Shell(CS)was used as a natural bio-adsorbent.The characterizations of CS were investigated by Fourier transform infrared(FTIR),X-ray diffraction(XRD),scanning electron microscopy(SEM),energy-dispersive X-ray spectroscopy(EDX)and Brunauer–Emmett–Teller(BET).The adsorption potential of Cockle Shells was tested in two cases(single and binary system)and determined by:contact time(0–60 min),bio-adsorption dose(3–15 g/L),initial concentration(10–300 mg/L),temperature(22–61°C)and pH solution(2–12).The study of bio-adsorption(equilibrium and kinetics)was conducted at 22°C.The kinetic studies demon-strated that a pseudo-second-order adsorption mechanism had a good correlation coefficient(R2≥0.999).The Langmuir isotherm modeling provided a well-defined description of TR and CG-H3G bio-adsorption on cockle shells,exhibiting maximum capacities of 29.41 and 3.69 mg/g respectively at 22°C.The thermodynamic study shows that the reaction between the TR,CG-H3G dyes molecules and the bio-adsorbent is exothermic,spontaneous in the range of 22–31°C with the aleatory character decrease at the solid-liquid interface.The study of selectivity in single and binary systems has been performed under optimal operating conditions using the industrial textile rejection pH(pH=6.04).CG-H3G dye is found to have a higher selectivity than TR in single(0–60 min)and binary systems with a range of 6–45 min,as shown by the selectivity measurement.It was discovered that CS has the capability to remove both CG-H3G and TR dyes in both simple and binary systems,making it a superior bio-adsorbent.展开更多
Clays are a constituent of the earth. As a result, the discovery and traditional use of clays in construction and pottery worldwide dates back to antiquity. Guinea has several deposits of clay minerals whose chemical ...Clays are a constituent of the earth. As a result, the discovery and traditional use of clays in construction and pottery worldwide dates back to antiquity. Guinea has several deposits of clay minerals whose chemical and mineralogical compositions have been little studied. Despite lacking of scientific data on these clay minerals, they are used today in pottery and habitat construction. As a step towards promoting the use of clay materials in Guinea, we conducted a study of the physicochemical and mineralogical properties of three natural clays from Kakan in the Republic of Guinea (AKKB, AKKE, AKKO) used in habitat construction. The aims of this work were to better understand their properties, but above all to be able to act on them to improve and broaden their applications, which until now have been limited to construction. These clays were studied by X-ray diffraction (XRD), X-ray fluorescence spectrometry (XRF), moisture content (%W), laser granulometry, Atterberg limits, specific surface area, infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), thermogravimetric analysis and differential thermal analysis (TGA/DTA). These analyses revealed that the main clay minerals present in our samples are kaolinite, illite and, montmorillonite, with the addition of impurities, the most abundant of which is quartz.展开更多
We present a study of the ion stopping power due to free and bound electrons in a warm dense plasma.Our main goal is to propose a method of stopping-power calculation expected to be valid for any ionization degree.The...We present a study of the ion stopping power due to free and bound electrons in a warm dense plasma.Our main goal is to propose a method of stopping-power calculation expected to be valid for any ionization degree.The free-electron contribution is described by the Maynard–Deutsch–Zimmerman formula,and the bound-electron contribution relies on the Bethe formula with corrections,in particular taking into account density and shell effects.The results of the bound-state computation using three different parametric potentials are investigated within the Garbet formalism for the mean excitation energy.The first parametric potential is due to Green,Sellin,and Zachor,the second one was proposed by Yunta,and the third one was introduced by Klapisch in the framework of atomic-structure computations.The results are compared with those of self-consistent average-atom calculations.This approach correctly bridges the limits of neutral and fully ionized matter.展开更多
This study examines the influence of magnetic field and temperature on the transient voltage of a polycrystalline silicon radial junction solar cell in a dynamic regime under multispectral illumination. Radial junctio...This study examines the influence of magnetic field and temperature on the transient voltage of a polycrystalline silicon radial junction solar cell in a dynamic regime under multispectral illumination. Radial junction solar cells represent a major advancement in photovoltaic technologies, as they optimize light absorption and charge collection efficiency. The focus is on the impact of the magnetic field and temperature on the decay of transient voltage, which provides crucial information on recombination processes and the lifetime of minority carriers. The results reveal that the magnetic field tends to increase the transient voltage by directly affecting the transient electron density. Indeed, for B > 7 × 10−5 T, the magnetic field prolongs the relaxation time by increasing the transient voltage amplitude. Additionally, rising temperatures accelerate (ranging from 290 K to 450 K) recombination processes, thereby reducing the transient voltage, although this effect is moderated by the presence of a magnetic field. The study highlights the complex interaction between magnetic field and temperature, with significant impacts on the transient behaviour.展开更多
This work aims at the mathematical modeling of a parabolic trough concentrator, the numerical resolution of the resulting equation, as well as the simulation of the heat transfer fluid heating process. To do this, a t...This work aims at the mathematical modeling of a parabolic trough concentrator, the numerical resolution of the resulting equation, as well as the simulation of the heat transfer fluid heating process. To do this, a thermal balance was established for the heat transfer fluid, the absorber and the glass. This allowed us to establish an equation system whose resolution was done by the finite difference method. Then, a computer program was developed to simulate the temperatures of the heat transfer fluid, the absorber tube and the glass as a function of time and space. The numerical resolution made it possible to obtain the temperatures of the heat transfer fluid, the absorber and the glass. The simulation of the fluid heating process was done in one-hour time steps, from six in the morning to six in the afternoon. The results obtained show that the temperature difference between the inlet and the outlet of the sensor is very significant. These results obtained, regarding the variation of the temperatures of the heat transfer fluid, the absorber and the glass, as well as the powers and efficiency of the parabolic trough concentrator and various factors, allow for the improvement of the performances of our prototype.展开更多
Millet [Pennisetum glaucum (L.) R. Br. (Poaceae)] is one of the most widely consumed crops in Niger. Its production, despite the efforts of farmers, is confronted with weed problems, in particular Sesbania pachycarpa ...Millet [Pennisetum glaucum (L.) R. Br. (Poaceae)] is one of the most widely consumed crops in Niger. Its production, despite the efforts of farmers, is confronted with weed problems, in particular Sesbania pachycarpa DC. (Fabaceae). The aim of the present study in this area is to assess the impact of Sesbania pachycarpa on millet growth and yield. To achieve this objective, a completely randomized Fisher block design of twenty-four elementary plots was set up with four replications. The data collected were millet plant heights and plot yields. The data collected were subjected to analysis of variance and Duncan’s test at the 5% threshold for comparisons of mean heights and yields with the control kept clean from sowing to millet harvesting. The results showed the sensitivity of millet plants to Sesbania pachycarpa. The results revealed that the threshold density for damage could be estimated at 6 Sesbania pachycarpa plants/m2 and the critical interference period at the fourth week after sowing. This study showed that the presence of Sesbania pachycarpa influences millet yield. Indeed, the best yields were obtained in plots without Sesbania pachycarpa. Millet yield decreased with increasing Sesbania pachycarpa density. The average percentage yield reduction was 36.79%, with a minimum of 21.25% and a maximum of 80%. The findings of this study complete the efforts of developing weed control techniques in pearl millet fields densely populated with Sesbania pachycarpa.展开更多
The effect of a storage system on drying time and estimation of drying parameters of cocoa beans using an indirect solar dryer with a sensible heat energy storage system (stones which act as both absorber and heat sto...The effect of a storage system on drying time and estimation of drying parameters of cocoa beans using an indirect solar dryer with a sensible heat energy storage system (stones which act as both absorber and heat storage media) is the main subject of this article. This dryer, which uses stones as storage material and is made of wood and plywood, was used to dry a quantity of 5 kg of fermented cocoa beans. The drying parameters for the drying curves and the drying efficiency of cocoa beans were established and studied. The drying curves were modelled from semi-empirical models. The results showed that the moisture of cocoa beans decreased from 60% to 7% in wet basis. With a solar collector and drying efficiency of 40% and 34%, respectively. And this with a maximum average difference temperature between the drying air and the ambient temperature of 13.25˚C day or night. The best concordances are obtained with R2 values of 0.9983, 0.9843, 0.9813 and 0.9837 respectively from the models of Hii, Jena and Das, Demir et al. and Alibas.展开更多
Organic fertilizers generally come from agricultural co-products. Their valuation is therefore a major issue for sustainable development. The main objective of this study aims to develop an organic fertilizer derived ...Organic fertilizers generally come from agricultural co-products. Their valuation is therefore a major issue for sustainable development. The main objective of this study aims to develop an organic fertilizer derived from moringa leaves and cocoa pod husks that can improve soil quality and plant growth. The experimental design consisted of completely randomized blocks in three repetitions. The experiment was carried out in five treatments: T0: no fertilization, T1: 100% cocoa pods, T2: 75% cocoa pods + 25% Moringa leaves;T3: 50% cocoa pods + 50% Moringa leaves;T4: 25% cocoa pods + 75% Moringa leaves;T5: 100% Moringa leaves. Three doses were applied: 1;2;4 kg/m2. The trial took place over three growing cycles. The results of the soil analysis compared to the control revealed a significant improvement in physicochemical parameters. Variation of pH from (6.1 to 7.2), calcium from (1.4 to 4.13), magnesium from (0.450 to 0.870), potassium from (0.096 to 0.365) cmol+/kg. Carbon and nitrogen were recorded (1.02% to 2.77%) and (0.12% to 2.56%) respectively. The CEC (cation exchange capacity) saw a clear improvement (4.2 to 9.03) cmol+/kg. Concerning the growth parameters, the control plants recorded an average height of (31.19 cm) while those that benefited from the treatments oscillated between (55.51 to 105.57 cm). In terms of production, the best yields are attributed to treatments T3 and T4 with (37.66 t/ha) and (51.176 t/ha) respectively. The T3 and T4 formulations could help improve the fertility of agricultural soils and the yield of market garden products such as eggplant.展开更多
This work reports a soft chemistry approach for the synthesis of magnesium oxide nanoparticles(MgO)incorporated in a polyaniline(PANI)matrix to give PANI/MgO nanocomposite.Using spin coating method,three different per...This work reports a soft chemistry approach for the synthesis of magnesium oxide nanoparticles(MgO)incorporated in a polyaniline(PANI)matrix to give PANI/MgO nanocomposite.Using spin coating method,three different percentages of MgO/PVC(1,2,and 3%in wt.%)were deposited on glass substrates.These films of PANI/MgO nanocomposite were characterized by X-ray diffraction(XRD),atomic force microscopy(AFM),and UV-visible spectroscopy.The results of the XRD pattern revealed the embedding of MgO nanoparticles in the PANI matrix with cubic phase,with the average size of nanoparticles varying from 35.12 to 59.55 nm.The AFM images displayed a significant change in the morphology of the PANI/MgO NPs composite films as MgO concentration was increased.The optical transmittance analysis revealed that at very low concentrations of MgO in PANI/MgO nanocomposite films,there is a high transparency,reaching close to 90%.However,this transmittance decreases significantly as the concentration of MgO increases.The photocatalytic activity of the nanocomposite film was then evaluated for the degradation of methylene blue(MB)dye under UV light irradiation.The results indicated a strong potential for PANI/MgO nanocomposite films in effectively degrading MB,supported by a proposed mechanism for the photocatalytic reaction.Compared with other composites such as PVC/MgO,PANI/MgO nanocomposite presented better MB degradation efficiency.展开更多
This review explores the research activities surrounding the development and integration of smart electricity grids in Burkina Faso, a landlocked and arid territory in West Africa and one of the poorest countries in t...This review explores the research activities surrounding the development and integration of smart electricity grids in Burkina Faso, a landlocked and arid territory in West Africa and one of the poorest countries in the world with significant energy challenges. It examines the current state of energy infrastructure in Burkina Faso, focusing on the integration of renewable energy sources, particularly solar photovoltaics. It highlights the role of smart grid technologies in enabling the efficient integration of renewable energy, improving grid stability and facilitating rural electrification. Additionally, the review addresses key challenges such as inadequate infrastructure, regulatory gaps and financial constraints that hinder the deployment of smart grids in the country. By analysing existing research and ongoing projects, this paper provides a comprehensive overview of the opportunities and barriers to implementing a smart electricity grid in Burkina Faso and offers recommendations for future development and policy frameworks.展开更多
This review examines the state-of-the-art in spatial manipulation of ultrafast laser processing using dynamic light modulators,with a particular focus on liquid crystal-based systems.We discuss phase modulation strate...This review examines the state-of-the-art in spatial manipulation of ultrafast laser processing using dynamic light modulators,with a particular focus on liquid crystal-based systems.We discuss phase modulation strategies and highlight the current limitations and challenges in surface and bulk processing.Specifically,we emphasize the delicate balance between high-fidelity beam shaping and energy efficiency,both critical for surface and bulk processing applications.Given the inherent physical limitations of spatial light modulators such as spatial resolution,fill factor,and phase modulation range.We explore techniques developed to bridge the gap between desired intensity distributions and actual experimental beam profiles.We present various laser light modulation technologies and the main algorithmic strategies for obtaining modulation patterns.The paper includes application examples across a wide range of fields,from surgery to surface structuring,cutting,bulk photo-inscription of optical functions,and additive manufacturing,highlighting the significant enhancements in processing speed and precision due to spatial beam shaping.The diverse applications and the technological limitations underscore the need for adapted modulation pattern calculation methods.We discuss several advancements addressing these challenges,involving both experimental and algorithmic developments,including the recent incorporation of artificial intelligence.Additionally,we cover recent progress in phase and pulse front control based on spatial modulators,which introduces an extra control parameter for light excitation with high potential for achieving more controlled processing outcomes.展开更多
基金The authors extend their appreciation to King Saud University,Saudi Arabia for funding this work through the Ongoing Research Funding Program(ORF-2025-704),King Saud University,Riyadh,Saudi Arabia.
文摘A novel siphon-based divide-and-conquer(SbDaC)policy is presented in this paper for the synthesis of Petri net(PN)based liveness-enforcing supervisors(LES)for flexible manufacturing systems(FMS)prone to deadlocks or livelocks.The proposed method takes an uncontrolled and bounded PN model(UPNM)of the FMS.Firstly,the reduced PNM(RPNM)is obtained from the UPNM by using PN reduction rules to reduce the computation burden.Then,the set of strict minimal siphons(SMSs)of the RPNM is computed.Next,the complementary set of SMSs is computed from the set of SMSs.By the union of these two sets,the superset of SMSs is computed.Finally,the set of subnets of the RPNM is obtained by applying the PN reduction rules to the superset of SMSs.All these subnets suffer from deadlocks.These subnets are then ordered from the smallest one to the largest one based on a criterion.To enforce liveness on these subnets,a set of control places(CPs)is computed starting from the smallest subnet to the largest one.Once all subnets are live,this process provides the LES,consisting of a set of CPs to be used for the UPNM.The live controlled PN model(CPNM)is constructed by merging the LES with the UPNM.The SbDaC policy is applicable to all classes of PNs related to FMS prone to deadlocks or livelocks.Several FMS examples are considered from the literature to highlight the applicability of the SbDaC policy.In particular,three examples are utilized to emphasize the importance,applicability and effectiveness of the SbDaC policy to realistic FMS with very large state spaces.
基金the World Climate Research Programme(WCRP),Climate Variability and Predictability(CLIVAR),and Global Energy and Water Exchanges(GEWEX)for facilitating the coordination of African monsoon researchsupport from the Center for Earth System Modeling,Analysis,and Data at the Pennsylvania State Universitythe support of the Office of Science of the U.S.Department of Energy Biological and Environmental Research as part of the Regional&Global Model Analysis(RGMA)program area。
文摘In recent years,there has been an increasing need for climate information across diverse sectors of society.This demand has arisen from the necessity to adapt to and mitigate the impacts of climate variability and change.Likewise,this period has seen a significant increase in our understanding of the physical processes and mechanisms that drive precipitation and its variability across different regions of Africa.By leveraging a large volume of climate model outputs,numerous studies have investigated the model representation of African precipitation as well as underlying physical processes.These studies have assessed whether the physical processes are well depicted and whether the models are fit for informing mitigation and adaptation strategies.This paper provides a review of the progress in precipitation simulation overAfrica in state-of-the-science climate models and discusses the major issues and challenges that remain.
文摘Nitrate contamination of groundwater is a worldwide problem, particularly in agricultural countries. Exposure to high levels of nitrates in groundwater can have adverse effects on the health of residents who use groundwater for drinking. This study aims to assess the health risk associated with the ingestion of nitrates in well water in the town of M’bahiakro. Health risk maps were created on the basis of hazard quotients (HQ) using the US Environmental Protection Agency (USEPA) health risk assessment model. The results indicate that residents of the Koko, Dougouba and Baoulekro neighbourhoods, whatever their age, are potentially exposed to the toxic effects of NO3−during their daily intake of nitrate-contaminated well water, with reference to hazard quotients (HQ) greater than 1. Nitrate concentrations in the groundwater should therefore be controlled in order to prevent their harmful effects on the health of the population and guarantee its use in rice-growing activities in M’Bahiakro.
文摘The objective of this study is to propose an optimal plant design for blue hydrogen production aboard a liquefiednatural gas(LNG)carrier.This investigation focuses on integrating two distinct processes—steam methanereforming(SMR)and ship-based carbon capture(SBCC).The first refers to the common practice used to obtainhydrogen from methane(often derived from natural gas),where steam reacts with methane to produce hydrogenand carbon dioxide(CO_(2)).The second refers to capturing the CO_(2) generated during the SMR process on boardships.By capturing and storing the carbon emissions,the process significantly reduces its environmental impact,making the hydrogen production“blue,”as opposed to“grey”(which involves CO_(2) emissions without capture).For the SMR process,the analysis reveals that increasing the reformer temperature enhances both the processperformance and CO_(2) emissions.Conversely,a higher steam-to-carbon(s/c)ratio reduces hydrogen yield,therebydecreasing thermal efficiency.The study also shows that preheating the air and boil-off gas(BOG)before theyenter the combustion chamber boosts overall efficiency and curtails CO_(2) emissions.In the SBCC process,puremonoethanolamine(MEA)is employed to capture the CO_(2) generated by the exhaust gases from the SMR process.The results indicate that with a 90%CO_(2) capture rate,the associated heat consumption amounts to 4.6 MJ perkilogram of CO_(2) captured.This combined approach offers a viable pathway to produce blue hydrogen on LNGcarriers while significantly reducing the carbon footprint.
文摘This study develops an analytical model to evaluate the cooling performance of a porous terracotta tubular direct evaporative heat and mass exchanger. By combining energy and mass balance equations with heat and mass transfer coefficients and air psychrometric correlations, the model provides insights into the impact of design and operational parameters on the exchanger cooling performance. Validated against an established numerical model, it accurately simulates cooling behavior with a Root Mean Square Deviation of 0.43 - 1.18˚C under varying inlet air conditions. The results show that tube geometry, including equivalent diameter, flatness ratio, and length significantly influences cooling outcomes. Smaller diameters enhance wet-bulb effectiveness but reduce cooling capacity, while increased flatness and length improve both. For example, extending the flatness ratio of a 15 mm diameter, 0.6 m long tube from 1 (circular) to 4 raises the exchange surface area from 0.028 to 0.037 m2, increasing wet-bulb effectiveness from 60% to 71%. Recommended diameters range from 5 mm for tubes under 0.5 m to 1 cm for tubes 0.5 to 1 m in length. Optimal air velocities depend on tube length: 1 m/s for tubes under 0.8 m, 1.5 m/s for lengths of 0.8 to 1.2 m, and up to 2 m/s for longer tubes. This model offers a practical alternative to complex numerical and CFD methods, with potential applications in cooling tower optimization for thermal and nuclear power plants and geothermal heat exchangers.
文摘Introduction: Renal ischemia-reperfusion (IR) is responsible for injuries such as destruction or dysfunction of tubular epithelial cells with inflammatory reaction and oxidative stress. Several therapeutic methods have been tested to alleviate ischemia-perfusion injury, ranging from using anti-inflammatory drugs, antioxidants, and plants from traditional pharmacopeia to administering RNA interference. However, there is currently no effective therapeutic option available for the treatment of renal IR injury, other than supportive therapies such as renal replacement therapy or hydration. Objective: This present study aimed to evaluate the effect of Guiera senegalensis on renal ischemia reperfusion, a recognized plant for its antioxidant and anti-inflammatory properties. Materials and Methods: Twenty-four (24) adult male Wistar rats were divided into four following groups: SLAM (subjected to a median laparotomy with simulated ischemia);GUIERRA (animals that received 250 mg/kg of guierra senegalensis orally, once a day, for 5 days, with simulated renal ischemia);IR (animals that underwent laparotomy followed by clamping of bilateral renal pedicles for 45 min and followed by reperfusion);GUIERRA + IR (animals given GUIERRA at the dosage of 250 mg/kg per day, for 5 days and then subjected to renal ischemia-reperfusion). Data analysis was performed by ANOVA, and a significance level of p Results: Compared with the I/R group, rats in the GUIERRA + IR group showed reduced histopathological damage scores (p Conclusion: The results of this preliminary work suggest that Guiera senegalensis decreases the degree of tissue damage in renal ischemia-reperfusion cases. This plant seems to be a promising therapeutic;further studies could help to precise the targets of its compounds on ischemia-reperfusion pathways.
基金supported by the University Salah Boubnider-Constantine 3 (Algeria).
文摘This research aims to study the bio-adsorption process of two dyes,Cibacron Green H3G(CG-H3G)and Terasil Red(TR),in a single system and to bring them closer to the industrial textile discharge by a binary mixture of two dyes(TR+CG-H3G).The Cockle Shell(CS)was used as a natural bio-adsorbent.The characterizations of CS were investigated by Fourier transform infrared(FTIR),X-ray diffraction(XRD),scanning electron microscopy(SEM),energy-dispersive X-ray spectroscopy(EDX)and Brunauer–Emmett–Teller(BET).The adsorption potential of Cockle Shells was tested in two cases(single and binary system)and determined by:contact time(0–60 min),bio-adsorption dose(3–15 g/L),initial concentration(10–300 mg/L),temperature(22–61°C)and pH solution(2–12).The study of bio-adsorption(equilibrium and kinetics)was conducted at 22°C.The kinetic studies demon-strated that a pseudo-second-order adsorption mechanism had a good correlation coefficient(R2≥0.999).The Langmuir isotherm modeling provided a well-defined description of TR and CG-H3G bio-adsorption on cockle shells,exhibiting maximum capacities of 29.41 and 3.69 mg/g respectively at 22°C.The thermodynamic study shows that the reaction between the TR,CG-H3G dyes molecules and the bio-adsorbent is exothermic,spontaneous in the range of 22–31°C with the aleatory character decrease at the solid-liquid interface.The study of selectivity in single and binary systems has been performed under optimal operating conditions using the industrial textile rejection pH(pH=6.04).CG-H3G dye is found to have a higher selectivity than TR in single(0–60 min)and binary systems with a range of 6–45 min,as shown by the selectivity measurement.It was discovered that CS has the capability to remove both CG-H3G and TR dyes in both simple and binary systems,making it a superior bio-adsorbent.
文摘Clays are a constituent of the earth. As a result, the discovery and traditional use of clays in construction and pottery worldwide dates back to antiquity. Guinea has several deposits of clay minerals whose chemical and mineralogical compositions have been little studied. Despite lacking of scientific data on these clay minerals, they are used today in pottery and habitat construction. As a step towards promoting the use of clay materials in Guinea, we conducted a study of the physicochemical and mineralogical properties of three natural clays from Kakan in the Republic of Guinea (AKKB, AKKE, AKKO) used in habitat construction. The aims of this work were to better understand their properties, but above all to be able to act on them to improve and broaden their applications, which until now have been limited to construction. These clays were studied by X-ray diffraction (XRD), X-ray fluorescence spectrometry (XRF), moisture content (%W), laser granulometry, Atterberg limits, specific surface area, infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), thermogravimetric analysis and differential thermal analysis (TGA/DTA). These analyses revealed that the main clay minerals present in our samples are kaolinite, illite and, montmorillonite, with the addition of impurities, the most abundant of which is quartz.
文摘We present a study of the ion stopping power due to free and bound electrons in a warm dense plasma.Our main goal is to propose a method of stopping-power calculation expected to be valid for any ionization degree.The free-electron contribution is described by the Maynard–Deutsch–Zimmerman formula,and the bound-electron contribution relies on the Bethe formula with corrections,in particular taking into account density and shell effects.The results of the bound-state computation using three different parametric potentials are investigated within the Garbet formalism for the mean excitation energy.The first parametric potential is due to Green,Sellin,and Zachor,the second one was proposed by Yunta,and the third one was introduced by Klapisch in the framework of atomic-structure computations.The results are compared with those of self-consistent average-atom calculations.This approach correctly bridges the limits of neutral and fully ionized matter.
文摘This study examines the influence of magnetic field and temperature on the transient voltage of a polycrystalline silicon radial junction solar cell in a dynamic regime under multispectral illumination. Radial junction solar cells represent a major advancement in photovoltaic technologies, as they optimize light absorption and charge collection efficiency. The focus is on the impact of the magnetic field and temperature on the decay of transient voltage, which provides crucial information on recombination processes and the lifetime of minority carriers. The results reveal that the magnetic field tends to increase the transient voltage by directly affecting the transient electron density. Indeed, for B > 7 × 10−5 T, the magnetic field prolongs the relaxation time by increasing the transient voltage amplitude. Additionally, rising temperatures accelerate (ranging from 290 K to 450 K) recombination processes, thereby reducing the transient voltage, although this effect is moderated by the presence of a magnetic field. The study highlights the complex interaction between magnetic field and temperature, with significant impacts on the transient behaviour.
文摘This work aims at the mathematical modeling of a parabolic trough concentrator, the numerical resolution of the resulting equation, as well as the simulation of the heat transfer fluid heating process. To do this, a thermal balance was established for the heat transfer fluid, the absorber and the glass. This allowed us to establish an equation system whose resolution was done by the finite difference method. Then, a computer program was developed to simulate the temperatures of the heat transfer fluid, the absorber tube and the glass as a function of time and space. The numerical resolution made it possible to obtain the temperatures of the heat transfer fluid, the absorber and the glass. The simulation of the fluid heating process was done in one-hour time steps, from six in the morning to six in the afternoon. The results obtained show that the temperature difference between the inlet and the outlet of the sensor is very significant. These results obtained, regarding the variation of the temperatures of the heat transfer fluid, the absorber and the glass, as well as the powers and efficiency of the parabolic trough concentrator and various factors, allow for the improvement of the performances of our prototype.
文摘Millet [Pennisetum glaucum (L.) R. Br. (Poaceae)] is one of the most widely consumed crops in Niger. Its production, despite the efforts of farmers, is confronted with weed problems, in particular Sesbania pachycarpa DC. (Fabaceae). The aim of the present study in this area is to assess the impact of Sesbania pachycarpa on millet growth and yield. To achieve this objective, a completely randomized Fisher block design of twenty-four elementary plots was set up with four replications. The data collected were millet plant heights and plot yields. The data collected were subjected to analysis of variance and Duncan’s test at the 5% threshold for comparisons of mean heights and yields with the control kept clean from sowing to millet harvesting. The results showed the sensitivity of millet plants to Sesbania pachycarpa. The results revealed that the threshold density for damage could be estimated at 6 Sesbania pachycarpa plants/m2 and the critical interference period at the fourth week after sowing. This study showed that the presence of Sesbania pachycarpa influences millet yield. Indeed, the best yields were obtained in plots without Sesbania pachycarpa. Millet yield decreased with increasing Sesbania pachycarpa density. The average percentage yield reduction was 36.79%, with a minimum of 21.25% and a maximum of 80%. The findings of this study complete the efforts of developing weed control techniques in pearl millet fields densely populated with Sesbania pachycarpa.
文摘The effect of a storage system on drying time and estimation of drying parameters of cocoa beans using an indirect solar dryer with a sensible heat energy storage system (stones which act as both absorber and heat storage media) is the main subject of this article. This dryer, which uses stones as storage material and is made of wood and plywood, was used to dry a quantity of 5 kg of fermented cocoa beans. The drying parameters for the drying curves and the drying efficiency of cocoa beans were established and studied. The drying curves were modelled from semi-empirical models. The results showed that the moisture of cocoa beans decreased from 60% to 7% in wet basis. With a solar collector and drying efficiency of 40% and 34%, respectively. And this with a maximum average difference temperature between the drying air and the ambient temperature of 13.25˚C day or night. The best concordances are obtained with R2 values of 0.9983, 0.9843, 0.9813 and 0.9837 respectively from the models of Hii, Jena and Das, Demir et al. and Alibas.
文摘Organic fertilizers generally come from agricultural co-products. Their valuation is therefore a major issue for sustainable development. The main objective of this study aims to develop an organic fertilizer derived from moringa leaves and cocoa pod husks that can improve soil quality and plant growth. The experimental design consisted of completely randomized blocks in three repetitions. The experiment was carried out in five treatments: T0: no fertilization, T1: 100% cocoa pods, T2: 75% cocoa pods + 25% Moringa leaves;T3: 50% cocoa pods + 50% Moringa leaves;T4: 25% cocoa pods + 75% Moringa leaves;T5: 100% Moringa leaves. Three doses were applied: 1;2;4 kg/m2. The trial took place over three growing cycles. The results of the soil analysis compared to the control revealed a significant improvement in physicochemical parameters. Variation of pH from (6.1 to 7.2), calcium from (1.4 to 4.13), magnesium from (0.450 to 0.870), potassium from (0.096 to 0.365) cmol+/kg. Carbon and nitrogen were recorded (1.02% to 2.77%) and (0.12% to 2.56%) respectively. The CEC (cation exchange capacity) saw a clear improvement (4.2 to 9.03) cmol+/kg. Concerning the growth parameters, the control plants recorded an average height of (31.19 cm) while those that benefited from the treatments oscillated between (55.51 to 105.57 cm). In terms of production, the best yields are attributed to treatments T3 and T4 with (37.66 t/ha) and (51.176 t/ha) respectively. The T3 and T4 formulations could help improve the fertility of agricultural soils and the yield of market garden products such as eggplant.
文摘This work reports a soft chemistry approach for the synthesis of magnesium oxide nanoparticles(MgO)incorporated in a polyaniline(PANI)matrix to give PANI/MgO nanocomposite.Using spin coating method,three different percentages of MgO/PVC(1,2,and 3%in wt.%)were deposited on glass substrates.These films of PANI/MgO nanocomposite were characterized by X-ray diffraction(XRD),atomic force microscopy(AFM),and UV-visible spectroscopy.The results of the XRD pattern revealed the embedding of MgO nanoparticles in the PANI matrix with cubic phase,with the average size of nanoparticles varying from 35.12 to 59.55 nm.The AFM images displayed a significant change in the morphology of the PANI/MgO NPs composite films as MgO concentration was increased.The optical transmittance analysis revealed that at very low concentrations of MgO in PANI/MgO nanocomposite films,there is a high transparency,reaching close to 90%.However,this transmittance decreases significantly as the concentration of MgO increases.The photocatalytic activity of the nanocomposite film was then evaluated for the degradation of methylene blue(MB)dye under UV light irradiation.The results indicated a strong potential for PANI/MgO nanocomposite films in effectively degrading MB,supported by a proposed mechanism for the photocatalytic reaction.Compared with other composites such as PVC/MgO,PANI/MgO nanocomposite presented better MB degradation efficiency.
文摘This review explores the research activities surrounding the development and integration of smart electricity grids in Burkina Faso, a landlocked and arid territory in West Africa and one of the poorest countries in the world with significant energy challenges. It examines the current state of energy infrastructure in Burkina Faso, focusing on the integration of renewable energy sources, particularly solar photovoltaics. It highlights the role of smart grid technologies in enabling the efficient integration of renewable energy, improving grid stability and facilitating rural electrification. Additionally, the review addresses key challenges such as inadequate infrastructure, regulatory gaps and financial constraints that hinder the deployment of smart grids in the country. By analysing existing research and ongoing projects, this paper provides a comprehensive overview of the opportunities and barriers to implementing a smart electricity grid in Burkina Faso and offers recommendations for future development and policy frameworks.
基金supported by the French ANRT agence nationale de la recherche technologique under the CIFRE conventions industrielles de formation par la recherche framework.
文摘This review examines the state-of-the-art in spatial manipulation of ultrafast laser processing using dynamic light modulators,with a particular focus on liquid crystal-based systems.We discuss phase modulation strategies and highlight the current limitations and challenges in surface and bulk processing.Specifically,we emphasize the delicate balance between high-fidelity beam shaping and energy efficiency,both critical for surface and bulk processing applications.Given the inherent physical limitations of spatial light modulators such as spatial resolution,fill factor,and phase modulation range.We explore techniques developed to bridge the gap between desired intensity distributions and actual experimental beam profiles.We present various laser light modulation technologies and the main algorithmic strategies for obtaining modulation patterns.The paper includes application examples across a wide range of fields,from surgery to surface structuring,cutting,bulk photo-inscription of optical functions,and additive manufacturing,highlighting the significant enhancements in processing speed and precision due to spatial beam shaping.The diverse applications and the technological limitations underscore the need for adapted modulation pattern calculation methods.We discuss several advancements addressing these challenges,involving both experimental and algorithmic developments,including the recent incorporation of artificial intelligence.Additionally,we cover recent progress in phase and pulse front control based on spatial modulators,which introduces an extra control parameter for light excitation with high potential for achieving more controlled processing outcomes.
